When it comes to modifying small displacement engines - and believe us, we've been doing this a long time - our favorite weapon of choice is the modern marvel we call the turbocharger. Although the supercharger has always been a popular alternative, the turbo is still king when it comes to tuning cars, and it almost seems cooler and sexier for some reason. For example: we've seen generations of OE manufacturers integrating it into some of the most famous and beloved cars to ever hit the streets, like the Supra, MR2 or Silvia - and today, turbocharged factory engines continue to delight enthusiasts with the Evo X, STI and Hyundai's new Genesis coupe. But chances are that if you're reading this, you probably don't have a car that came turbocharged stock and you wouldn't be happy settling with anything stock. We all want more power, right? That means it's time to turbocharge that ish. But where do you start? With all the choices in selecting a turbo for your engine and driving style, figuring out which turbo is right can be a task unto its own. And that's why we're here; we're your shoulder to lean on - just look over your shoulders, honey!
Before we dive into turbocharging, let's go over a few basics. In its simplest form, your engine is a huge pump and it's limited to the amount of air that it can breathe on its own. A turbocharger increases the amount of air that an engine can aspirate (inhale) by force-feeding it air. Hence the term "forced induction". Or as we like to say: more air and fuel equals more power. But like your girlfriend's taste in handbags, it's never that easy.
How Does Turbocharging Work?
We know what you're thinking, "Thanks Captain Obvious; we know turbos make power," but how does that snail do it? The engine produces exhaust gases that flow through the turbo manifold, which are then funneled into the turbocharger's turbine inlet. The movement of these gases cause the turbine wheel to spool (spin) as they pass through on their way out your muffler. Since the turbine wheel is directly connected to the compressor wheel, as the turbine wheel spools faster, the compressor wheel will start to draw air in. At the same time it's drawing in, it's also pushing air out, similar to how a blow dryer operates. The volume of air increases to a point that it becomes compressed and charged (boost). But this air is usually heated as the turbocharger gets its energy from the spent exhaust gases. To cool down the air charge, the air passes through an intercooler to keep intake air temps in check (the cooler the temperature, the more efficient the motor becomes). This air then makes its way into the engine, forcing itself into the combustion chamber. This extra amount of air increases the volumetric efficiency of the engine, the byproduct of which is increased power. The spent gasses are then pushed out to reciprocate the process.
How Do I Choose the Right Turbo?
With so many choices in turbos out there to choose from, figuring out which turbo is right for you can be complicated. Lucky for you there are a few manufacturers who specialize in the art of turbocharging, like our special guests today: HKS, GReddy, Garrett and Turbonetics. Before you go out and spend your hard-earned cash, we recommend sitting down and building a game plan for your engine. What kind of power do you want to make and is it a realistic figure? Is your engine built or is it still stock? These are all important factors to think about because you have to consider how much power your engine can handle. Also, what kind of driving will you be doing? Is your project going to see any time on a track? Daily driver? This will help you figure out the target range of power that's right for you. Remember to also be honest with yourself at this stage; 500WHP isn't very realistic if you're drifting your S14 on the weekends or are going to sit in traffic on the daily with your Evo.